But is it secure? I favor OCaml or something similar. I think new languages often have bugs, and WREN is new. It may be high performance but if it's not secure then it will not be able to carry billions of dollars without the risk of bugs or obfuscated code.

I will look into WREN more but the virtual machine method of security is security by isolation, and we already see that approach failed with Solidity. As far as LISK goes, that's a joke in terms of security and no one should think it can do something serious.